Calculate the resistance of the filament of a lamp rates 240 V, 40 W

• A. 240Ω
• B. 360Ω
• C. 720Ω
• D. 1440Ω

A wire 1.0m long and with cross-sectional area 2.0 x 10^-7 m² has a resistance of 0.1\(\Omega\). Calculate the electrical conductivity of the wire

• A. 2.0 x 10⁷\(\Omega^{-1} m^{-1}\)
• B. 5.0 x 10⁷\(\Omega^{-1} m^{-1}\)
• C. 2.0 x 10⁸\(\Omega^{-1} m^{-1}\)
• D. 5.0 x 10⁸\(\Omega^{-1} m^{-1}\)

An air craft attempt too fly due north at 100 km/h. If the wind blows against it from east to west at 60 km/h, its resultant velocity is

• A) 117 km/h, N31^oE
• B) 127 km/h, N31^oE
• C) 117 km/h, N31^oW
• D) 127 km/h, N31^oW

During a thunderstorm, lightning and thunder occurred simultaneously in the atmosphere. An observer on the earth surface's sees the lightning flash shortly before hearing the thunder. This is because the

• A. atmospheric pressure is higher at the surface than at the higher altitudes
• B. speed of sound is less than that of light
• C. temperature of the atmosphere decreases with altitude
• D. atmospheric density decreases with altitude

Which of the following statements about a ferromagnetic material is correct? It

• A. has a high susceptibility.
• B. attracts non-magnetic materials.
• C. has low relative permeability.
• D. repels other magnetic materials.

A car starts from rest and covers a distance of 40m in 10s. Calculate the magnitude of its acceleration

• A. 0.25ms^-2
• B. 0.80ms^-2
• C. 3.20ms^-2
• D. 4.00ms^-2

Heat is supplied to a test tube containing 100g of ice at its melting point. The ice melts completely in 1 min.What is the power rating of the source of heat? [Latent heat of fusion of ice = 336Jg^-1]

• A. 336W
• B. 450W
• C. 560W
• D. 600W

Which of the following characteristics of waves can a ripple tank be used to demonstrate? I. Reflection II. Refraction III. Diffraction

• A. I, II and Ill
• B. ll and ll only
• C. l and lII only
• D. I and II only

A sounding tuning fork is brought near the open end of a pipe containing air and the loudness of the sound is observed to increase. This observation is due to

• A. an echo
• B. resonance
• C. interference
• D. reverbration

A car of mass 800kg moves from rest on a horizontal track and travels 60m in 20s with uniform acceleration. Assuming there were no frictional forces, calculate the accelerating force

• A. 240.0N
• B. 800.0N
• C. 1600.00N
• D. 2400.0N